Radionuclide angiography is frequently used to assess left ventricular function in patients with coronary artery disease. However, due to overlapping regions and the inherent limitation of applying planar, two- dimensional images to assess the function of a three-dimensional organ, direct correlation of tomographic perfusion defects with planar regional wall motion abnormalities may not be accurate. In this study, we compared tomographic radionuclide studies among 22 patients with chronic coronary artery disease who also had undergone planar radionuclide angiography. Both planar and tomographic wall motion were analyzed qualitatively by blinded readers as normal/hypokinetic, severely hypokinetic, or akinetic/dyskinetic. Tomographic radionuclide angiography images were displayed in 3 contiguous slices in horizontal long-axis, vertical long-axis and short-axis views. Among a total of 110 regions analyzed, planar and tomographic angiography studies provided concordant wall motion information in 84 (76%) regions. All 67 regions (100%) identified as normal or hypokinetic by tomography were also normal or hypokinetic by planar studies. Only 3 of 14 (21%) severe hypokinetic regions by tomography were identified as severe hypokinetic by planar radionuclide angiography; 9 were assigned normal/hypokinetic and 2 akinetic/dyskinetic. Similarly, only 14 of 29 (48%) akinetic/dyskinetic regions by tomography were identified as akinetic/dyskinetic by planar studies; 8 were assigned normal/hypokinetic and 7 as severe hypokinesis. In contrast, there were no regions that were assigned severe hypokinesis or akinesis/dyskinesis by planar radionuclide angiography that were interpreted as normal/hypokineitc by tomography. Therefore, tomographic radionuclide angiography detected a large number of wall motion abnormalities missed by planar imaging while none of planar severe hypokinetic or akinetic/dyskinetic regional wall motion abnormalities were missed by tomographic studies. In the absence of a gold standard, these data suggest that tomographic radionuclide angiography may identify more dysfunctional myocardial regions than planar imaging.